CVE-2026-7748
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA weakness has been identified in Totolink N300RH 3.2.4-B20220812. Affected by this issue is the function setUpgradeFW of the file /cgi-bin/cstecgi.cgi of the component POST Request Handler. Executing a manipulation of the argument FileName can lead to buffer overflow. The attack can be launched remotely. The exploit has been made available to the public and could be used for attacks.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA buffer overflow vulnerability exists in the Totolink N300RH router firmware (version 3.2.4-B20220812) within the cstecgi.cgi CGI binary. The overflow occurs in the setUpgradeFW function when processing the FileName parameter in HTTP POST requests, allowing remote attackers to potentially execute arbitrary code.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify device modelAccess the router web interface or check the device label/marketing to confirm the model is Totolink N300RHAffected if Device is not a Totolink N300RH router
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Check firmware versionLog into the router admin panel (usually at 192.168.1.1) and navigate to System Status or Firmware Version to view the installed firmware build. Alternatively, check the firmware file name if you have a firmware dumpAffected if Firmware version is 3.2.4-B20220812
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Verify cstecgi.cgi is presentAttempt to access the CGI binary via HTTP GET/POST to /cgi-bin/cstecgi.cgi on the router's web serverAffected if The cstecgi.cgi binary exists and is accessible on the device
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Confirm web management interface exposureCheck router firewall settings and network configuration to determine if the web management interface (port 80/443) is reachable from untrusted networksAffected if The router's web interface is exposed to WAN or untrusted networks rather than only LAN
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Check if setUpgradeFW function is enabledAnalyze the cstecgi.cgi binary (if accessible via firmware dump) to confirm the setUpgradeFW function exists in the binaryAffected if The setUpgradeFW function is present in the cstecgi.cgi binary
User is affected if they have a Totolink N300RH router running firmware version 3.2.4-B20220812 with the cstecgi.cgi interface accessible (especially from WAN) and the setUpgradeFW function present in the binary.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply available firmware patches; if no patch exists, replace the end-of-life device and/or restrict external access to the device's management interface using network segmentation and firewall rules.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-7748 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-7748 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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